H₂Blue is a reagent designed to detect the presence of dissolved hydrogen gas in water by performing what chemists call a "titration". In a titration, a substance of known concentration (the H₂Blue reagent) is added to a measured volume of water containing an unknown level of dissolved hydrogen gas (H₂) . In the presence of dissolved hydrogen gas, the H₂Blue molecules bond with the dissolved H₂ molecules, causing the blue molecules to turn "clear". As additional drops are added, the available dissolved hydrogen molecules are "consumed" until there are no more dissolved H₂ molecules in the water. This is called the "titration endpoint". When the endpoint has been reached, additional drops will no longer turn clear and the solution will remain blue. By counting the number of drops of H₂Blue required to reach the titration endpoint for 6 mL of water, and then multiplying the number of drops by 0.1, the level of dissolved H₂ gas in parts per million (ppm) can be determined. For example, 6 drops x 0.1 = 0.6 ppm of dissolved H₂. (ppm can also be expressed as mg/L)

H₂Blue is designed for testing dissolved H₂ levels in hydrogen water produced from water ionizers, hydrogen infusion machines (HIM's), tablets, sticks, etc. H₂Blue may not provide accurate results when used to test hydrogen water containing other dissolved gases such as Chlorine (Cl2) and Oxygen (O2), or dissolved compounds (such as Vitamin C). These can sometimes be found in hydrogen water produced by devices such as Brown's Gas generators or in beverages (such as orange juice) into which a hydrogen-gas reactor cartridge has been placed. The presence of other reductants/oxidants may produce incorrect results by interfering with the redox reaction between the dissolved H₂ gas and H₂Blue.

The H₂Blue spout is designed to dispense a precise droplet size for testing dissolved H₂ levels.  When dispensing each drop, turn the bottle completely upside down, squeeze the bottle until one drop exits the spout, then release the pressure (which creates a small vacuum). Repeat this for each ensuing drop. Dispensing H₂Blue in this way will help to prevent excess reagent from running down the spout.

• After completing each measurement, be sure to completely rinse the beaker to remove all H₂Blue residue. If H₂Blue residue is permitted to accumulate on the inside of the graduated beaker, this may result in inaccurate H₂ readings.

• Because dissolved hydrogen gas starts to escape immediately after the sample is taken, try to perform measurements as quickly as possible. Multiple drops of H₂Blue can be added to save time, but do not add too many, which may cause you to pass the titration endpoint.

• Fill the beaker directly from the device without using any type of intermediate container such as a drinking glass-hold the beaker at a slight angle while filling to prevent any splashing which may inadvertently force dissolved hydrogen gas out of the water.

• When doing measurements, avoid shaking the beaker, which can significantly reduce the dissolved H₂. It is better to use a small straw (such as a coffee stirrer or toothpick) to gently stir the drops into the sample water.

• When approaching the titration endpoint, be sure to count the last drop required to cause the sample to remain blue.